Revenue Recognition - Disaggregated Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	$ 111	$ 139	$ 335	$ 340
Lease revenue	14	14
Total revenue	125	153	377	382
Related Parties
Disaggregation of Revenue [Line Items]
Lease revenue			42	42
Transportation Services | Third Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	31	57	103	144
Transportation Services | Related Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	55	52	156	125
Storage Services | Third Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	2	1	6	6
Storage Services | Related Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	1	2	5	5
Terminaling Services | Related Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	12	12	35	34
Product Revenue | Third Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	0	1	4	2
Product Revenue | Related Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	10	14	26	24
Transportation Services, Non-lease Service | Related Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	$ 2	$ 2	$ 4	$ 4